A single-stage isolated three-phase ac-dc conversion circuit

Abstract

The application discloses a single-stage isolated three-phase AC / DC conversion circuit, which sequentially comprises a three-phase AC input end, an input filter module, a high-frequency isolation module, a three-phase full-bridge conversion module, a secondary resonant rectification module and a DC output module; the three-phase AC input end filters out the noise of input through the input filter module; the current filtered by the input filter module flows into the high-frequency isolation module; the primary side of a transformer in the high-frequency isolation module is connected with the midpoint of three bridge arms in the three-phase full-bridge conversion module, the secondary side of the transformer is connected with the secondary resonant rectification module, and the secondary resonant rectification module is connected to the DC output module after rectifying the current. The application realizes wide-area adaptation and topology reconstruction of three-phase / single-phase environment, can not only be used as a standard three-phase converter for efficient operation, but also can be downwardly compatible and reconstructed into a single-phase equivalent circuit, and realizes flexible switching of resonant and linear working states.

Description

Technical Field

[0001] This application relates to the field of three-phase rectification technology, and more particularly to a single-stage isolated three-phase AC / DC converter circuit. Background Technology

[0002] Currently, high-power three-phase AC-DC power conversion systems are widely used in industrial control, new energy storage, and electric vehicle charging piles.

[0003] Traditional three-phase power frequency rectifiers are typically bulky and heavy. To improve power density, the industry generally adopts a two-stage (e.g., front-end active rectification + subsequent DC / DC isolation converter) high-frequency isolation scheme. While this scheme reduces the overall size, it suffers from the problems of requiring a large number of fully controlled switching components and complex control links. This results in the superposition of switching and conduction losses in the overall circuit, leading to extremely high heat generation and severely limiting further improvements in system efficiency.

[0004] Furthermore, existing isolated three-phase converters typically employ three independent transformers for high-frequency isolation. This traditional design not only results in magnetic components occupying a large physical space but also makes it difficult to guarantee complete consistency in the three-phase magnetic circuit characteristics. Simultaneously, under extremely high-frequency switching operations, the active bridge arm generates a very large common-mode voltage, inducing severe zero-sequence common-mode noise at the grid end. To suppress this noise, a bulky and expensive common-mode filter inductor must be added at the front end, further deteriorating the overall power density and cost of the converter.

[0005] On the other hand, existing high-frequency converters are often designed for a single power supply environment (pure three-phase or pure single-phase). When faced with complex or degraded power supply networks (such as a phase loss in a three-phase grid, or the need for equipment to be temporarily connected to single-phase mains power), traditional three-phase hard topologies cannot be flexibly reconfigured to maintain normal operation, which greatly limits the environmental adaptability and application scenarios of the equipment.

[0006] Therefore, how to simultaneously achieve high-frequency isolation and AC-to-DC conversion in a single-stage circuit topology, while reducing system complexity and losses, and further solving problems such as the large size of independent magnetic components, high-frequency common-mode noise spillover, and incompatibility with single / three-phase power supply environments, is a key technical challenge that urgently needs to be solved in the field of power electronics. Summary of the Invention

[0007] This application aims to provide a highly integrated and environmentally adaptable power conversion solution. Addressing the issues of poor stability, bulky magnetic components, and nonlinear energy transfer in existing isolated converters under complex power supply environments, this application achieves comprehensive performance optimization through collaborative innovation in both hardware and software.

[0008] This application provides a single-stage isolated three-phase AC / DC converter circuit, which adopts the following technical solution: A single-stage isolated three-phase AC / DC converter circuit comprises, in sequence, a three-phase AC input terminal, an input filter module, a high-frequency isolation module, a three-phase full-bridge converter module, a secondary resonant rectifier module, and a DC output module. The three-phase AC input terminal receives the three-phase source into the circuit, which then passes through the input filter module to filter out input noise. The filtered current flows into the high-frequency isolation module. The primary winding of the transformer in the high-frequency isolation module is connected to the midpoint of the three bridge arms of the three-phase full-bridge converter module, while the secondary winding is connected to the secondary resonant rectifier module. The secondary resonant rectifier module rectifies the current and connects it to the DC output module.

[0009] The three-phase AC input terminal is connected to a three-phase AC power supply. , , ; , , Connected to the input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal.

[0010] In the input filtering module, the filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module Filter capacitor , and The other end is grounded.

[0011] In the high-frequency isolation module, the transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and The drain of the transformer One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end; transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Drain of transformer; One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end; transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Drain of transformer; One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end.

[0012] In the three-phase full-bridge converter module, the power switching transistors Drain, Drain and The drains are connected together and then connected to the bus capacitor. one end and the first resonant capacitor One end; power switching transistor The source pole, The source pole and The sources are connected together and connected to the bus capacitor. The other end and the second resonant capacitor One end; first resonant capacitor The other end and the second resonant capacitor The other end is grounded.

[0013] Optionally, the first resonant capacitor in the three-phase full-bridge converter module The first diode can be connected in parallel at both ends. Meanwhile, the second resonant capacitor A second diode is connected in parallel at both ends. First diode Second diode Alternatively, you can replace it with two switches.

[0014] In the secondary resonant rectifier module, the resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; rectifier diode cathode, cathode and The cathode is connected to the rectifier capacitor. The other end and the filter capacitor in the DC output module One end is connected; rectifier diode anode, anode and The anode is connected to the rectifier capacitor. The other end and the filter capacitor in the DC output module The other end is connected.

[0015] The DC output module includes an output filter capacitor. and load Output filter capacitor One end is connected to the rectifier diode. , , The cathode is connected to the rectifier diode at the other end. , , The anode. Equivalent to being connected in parallel with the rectifier capacitor. and The two ends. Load Parallel connection to the output filter capacitor Both ends. The current rectified by the secondary resonant rectifier module passes through the output filter capacitor. After filtering, the load is supplied. powered by.

[0016] In summary, the present invention has the following beneficial technical effects: 1. Wide-area adaptation and topology reconfiguration in three-phase / single-phase environments are achieved. Through the unidirectional conductivity characteristics of the first and second diodes and the reconfiguration logic, the circuit can not only operate efficiently as a standard three-phase converter, but also be backward compatible and reconfigured into a single-phase equivalent circuit.

[0017] 2. Flexible switching between resonant and linear operating states is achieved. In single-phase mode, the alternating conduction of diodes and resonant capacitors allows the circuit to smoothly transition between a pure resonant state for half a cycle and a linear state for half a cycle.

[0018] 3. Three-phase integrated magnetic cores (especially three-phase five-limb structures) can be used. While reducing the overall volume of magnetic components and optimizing interphase current sharing to suppress circulating current, its side yoke structure significantly suppresses zero-sequence high-frequency common-mode noise, thereby reducing the volume, magnetic saturation margin and material cost of the front-end filter inductor.

[0019] 4. The combination of three-phase interleaved energy replenishment and dual closed-loop control provides high-quality DC power with voltage multiplication and low ripple. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall topology of the three-phase AC / DC converter circuit provided in the embodiments of this application; Figure 2 A schematic diagram of the overall topology of the three-phase AC / DC converter circuit with single-phase / three-phase switching function provided in the embodiments of this application; Figure 3 The equivalent circuit diagram of the phase number reconstruction module provided in the embodiments of this application in single-phase mode; Figure 4 This is a schematic diagram showing the resonant inductor placed on the original transformer in an embodiment of this application; Figure 5 These are some simulated waveforms in the three-phase resonant mode of the embodiments of this application; Figure 6 The following are some simulation waveforms in the single-phase linear-resonant mode of the embodiments of this application. Detailed Implementation

[0021] The present application will be further described in detail below with reference to the accompanying drawings.

[0022] Example 1: This application discloses a single-stage isolated three-phase AC / DC converter circuit. (Refer to...) Figure 1 The circuit consists of a three-phase AC input terminal (10), an input filter module (20), a high-frequency isolation module (30), a three-phase full-bridge converter module (40), a secondary resonant rectifier module (50), and a DC output module (60), connected in sequence. The three-phase AC input terminal (10) inputs the three-phase source into the circuit, which then passes through the input filter module (20) to filter out the input noise. The filtered current from the input filter module (20) flows into the high-frequency isolation module (30). The primary side of the transformer in the high-frequency isolation module (30) is connected to the midpoint of the three bridge arms of the three-phase full-bridge converter module (40), and the secondary side of the transformer is connected to the secondary resonant rectifier module (50). The secondary resonant rectifier module (50) rectifies the current and then connects it to the DC output module (60).

[0023] The three-phase AC input terminal (10) is connected to a three-phase AC power supply. , , . , , The input terminal is connected. The output terminal is connected to the filter inductor in the input filter module. The input terminal. The output terminal is connected to the filter inductor in the input filter module. The input terminal. The output terminal is connected to the filter inductor in the input filter module. The input terminal.

[0024] The input filtering module (20) contains a three-phase front-end filter inductor. , , AC side filter capacitor , , Filter inductor Input terminal connected to The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. Filter inductor Input terminal connected to The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. Filter inductor Input terminal connected to The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. Filter capacitor One end is connected to the filter inductor and the primary side magnetizing inductor of the high-frequency isolation module One end is connected to the ground, and the other end is grounded. Filter capacitor. One end is connected to the filter inductor and the primary side magnetizing inductor of the high-frequency isolation module One end is connected to the ground, and the other end is grounded. Filter capacitor. One end is connected to the filter inductor and the primary side magnetizing inductor of the high-frequency isolation module Between the two ends, the other end is grounded.

[0025] The high-frequency isolation module (30) includes a three-phase transformer. , , .transformer excitation inductor One end is connected to the filter inductor The output of the circuit is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Between the drain and the transformer. One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. and Between. Transformer excitation inductor One end is connected to the filter inductor The output of the circuit is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Between the drain and the transformer. One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. and Between. Transformer excitation inductor One end is connected to the filter inductor The output of the circuit is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Between the drain and the transformer. One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. and between.

[0026] Optionally, the magnetizing inductance of the three transformers in the high-frequency isolation module , , Magnetic integration technology can be used to concentrate the three excitation inductors on the same integrated magnetic core. A three-phase three-limb magnetic core or a three-phase five-limb magnetic core can be selected.

[0027] By adopting the above technical solution, the magnetic flux excited by the three-phase current is vector-superimposed and canceled out in the common magnetic arm. This not only utilizes the magnetic coupling characteristics to achieve automatic current sharing and balancing of the three-phase power to suppress circulating current, but also significantly reduces the overall volume of the magnetic core. At the same time, if a three-phase five-limb magnetic core is used, its side yoke structure provides a loop for the zero-sequence magnetic flux, restoring the high impedance to the zero-sequence current. This significantly reduces the high-frequency noise flowing to the AC side filter capacitor and ground wire in the input filter module, thus allowing the use of a small-volume, low magnetic saturation margin front-end filter inductor, improving the overall power density and reducing material costs.

[0028] The three-phase full-bridge converter module (40) includes six power switching transistors of the three-phase full-bridge. , , , , , and bus capacitor and the first resonant capacitor Second resonant capacitor Power switching transistor The source pole and The drain is connected to the transformer. excitation inductor One end. Power switching transistor. The source pole and The drain is connected to the transformer. excitation inductor One end. Power switching transistor. The source pole and The drain is connected to the transformer. excitation inductor One end. Power switching transistor. , , The drains of the transistors are connected together and then connected to one end of the bus capacitor. Power switching transistor , , The sources are connected together and then connected to the other end of the bus capacitor. First resonant capacitor. One end is connected to the power switching transistor , , One end is the source, and the other end is grounded. Second resonant capacitor. One end is connected to the power switching transistor , , One end is the source, and the other end is grounded. Capacitor and It is connected in parallel across the bus capacitor.

[0029] Optionally, the second resonant capacitor in the three-phase full-bridge converter module It is possible to leave it unconnected and retain only the first resonant capacitor. .

[0030] By adopting the above technical solution, this circuit realizes a complete single-stage isolated high-frequency power conversion link. The input current, after being filtered by the input filter module and the magnetizing inductor of the high-frequency isolation module, enters the three-phase full-bridge converter module. Under the high-frequency alternating switching of the upper and lower switching transistors, the current flows through the bus capacitor... With the first resonant capacitor Second resonant capacitor Dynamically allocated between them. If the second resonant capacitor... Without connection, current flows through the bus capacitor. With the first resonant capacitor Although the number of components has decreased, the DC voltage of the power switching transistors will increase as the flow between them increases.

[0031] The secondary resonant rectifier module (50) contains three sets of resonant inductors. , , With DC blocking capacitor , , The series resonant cavity and the rectifier diodes , , , , , and rectifier capacitor , The rectifier branch is formed. Resonant inductor. One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end. Rectifier diode. anode and The cathode is connected and connected to the DC blocking capacitor. The other end. Resonant inductor. One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end. Rectifier diode. anode and The cathode is connected and connected to the DC blocking capacitor. The other end. Resonant inductor. One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end. Rectifier diode. anode and The cathode is connected and connected to the DC blocking capacitor. The other end. Rectifier diode. , , The cathode is connected. Rectifier diode. , , The anode is connected. Rectifier capacitor. One end is connected to the rectifier diode. , , Cathode and DC output module filter capacitors One end, the other end connected to One end of the rectifier capacitor. One end is connected to the rectifier diode. , , Filter capacitors in the anode and DC output modules One end, the other end connected to One end of the rectifier capacitor. and The connection point is connected to the high-frequency isolation module. , , The opposite terminal of the secondary winding.

[0032] Optionally, the resonant inductor in the secondary resonant rectifier module , , It can be placed on the primary side of the transformer in the high-frequency isolation module, and connected to the transformer respectively. , , of , , Series, such as Figure 4 As shown.

[0033] Optionally, the secondary resonant rectifier module can also use other rectifier circuits, such as full-bridge rectifiers, synchronous rectifiers, etc.

[0034] By adopting the above technical solution, the secondary circuit utilizes the inherent 120-degree phase shift of the three-phase primary circuit to achieve interleaved voltage multiplication rectification. The time-division injection of three-phase energy effectively compensates for the output voltage troughs, thereby significantly suppressing DC output ripple.

[0035] The DC output module (60) includes an output filter capacitor. and load Output filter capacitor One end is connected to the rectifier diode. , , The cathode is connected to the rectifier diode at the other end. , , The anode. Equivalent to being connected in parallel with the rectifier capacitor. and The two ends. Load Parallel connection to the output filter capacitor At both ends. The current rectified by the secondary resonant rectifier module passes through the output filter capacitor. After filtering, the load is supplied. powered by.

[0036] The control strategy employs dual closed-loop vector control. The system acquires the three-phase input voltage in a fixed phase and decouples the input current to the dq rotating coordinate system via Clark and Park transforms. The output voltage serves as the outer loop to maintain stability, while the dq-axis current serves as the inner loop to ensure power factor and response speed. Finally, the inverse transform generates six PWM signals to precisely drive the MOSFETs, completing the closed-loop design from physical topology to control algorithm. Control can employ either fixed-frequency or variable-frequency control.

[0037] By adopting the above technical solution, this circuit realizes a complete single-stage isolated high-frequency power conversion link. Input power is filtered by the input filter module and the magnetizing inductor of the high-frequency isolation module before entering the three-phase full-bridge converter module. Under the high-frequency alternating switching of the upper and lower switching transistors, the current is dynamically distributed between the bus capacitor and the resonant capacitor. If single-phase / three-phase switching is required, the first and second diodes can be connected to reconstruct the three-phase hard topology into a single-phase equivalent circuit, achieving wide-area adaptation. Subsequently, energy is coupled to the secondary resonant rectifier module via the secondary winding of the transformer in the high-frequency isolation module. Each secondary unit utilizes the current shaped by the resonant cavity, passes through voltage doubler rectification logic, and is filtered by the output filter capacitor of the DC output module before supplying power to the load.

[0038] The implementation principle of this application embodiment is as follows: the input current is filtered by the input filter module 20 and the magnetizing inductor of the high-frequency isolation module 30 before entering the three-phase full-bridge converter module 40, so that the primary current flows through the primary winding, the three-phase full-bridge converter module 40, and then returns to ground. Under the high-frequency alternating switching of the upper and lower power switches, the current is dynamically distributed between the bus capacitor and the first and second resonant capacitors, and the system operates in a pure resonant state. The magnetic flux excited by the three-phase current in the high-frequency isolation module 30 is vector-superimposed and canceled in the common magnetic arm, realizing automatic current sharing balance of the three-phase power to suppress circulating current; if a three-phase five-limb magnetic core is used, its side yoke structure provides a loop for the zero-sequence magnetic flux, which can significantly reduce high-frequency noise. Subsequently, the energy is coupled to the secondary resonant rectifier module 50, and the three-phase current alternately charges and discharges the shared rectifier capacitor through the rectifier diodes to realize the voltage multiplier rectification mechanism. The rectified current is filtered by the output filter capacitor and then supplies power to the load. The specific control strategy is as follows: the system acquires the three-phase input voltage to determine its phase, and decouples the input current to the dq rotating coordinate system through Clark and Park transformations; then, it uses the output voltage as the outer loop to maintain stability, and the dq-axis current as the inner loop to ensure power factor and response speed. Finally, it inversely transforms to generate six PWM signals to precisely drive the power switching transistors. Some simulation waveforms of this embodiment are shown below. Figure 5 As shown, where , , This is the three-phase input voltage. , , For three-phase input current, , , This is the excitation current for the three phases. This represents the DC output voltage. As shown in the figure, through dual closed-loop vector control, the input current can track the input voltage in steady state, achieving power factor correction, and ultimately stabilizing the output voltage.

[0039] Example 2: Reference Figure 2 The difference between this embodiment and Embodiment 1 is that the first resonant capacitor in the three-phase full-bridge converter module 40... First diode connected in parallel at both ends Meanwhile, the second resonant capacitor A second diode is connected in parallel at both ends. First diode Second diode Alternatively, two switches can be used. The equivalent circuit diagram for switching to single-phase is as follows: Figure 3 As shown.

[0040] The implementation principle of this application embodiment is as follows: the circuit can realize single-phase and three-phase switching. In three-phase mode, the circuit operates as a standard three-phase converter, working in a pure resonant state and possessing high power output capability. In single-phase mode, the first diode is used... Second diode Due to its unidirectional conductivity and topology reconfiguration logic, the circuit can be equivalently transformed into a single-phase isolated converter. During half a cycle, the current flows through the resonant capacitor, and the circuit enters a resonant state; in the other half cycle, the current flows through the diode to achieve clamping, and the circuit enters a linear operating state, thus achieving stable switching between linear and resonant circuits. Some simulation waveforms of embodiments of this application are shown below. Figure 6 As shown, where and It is a MOSFET and The drive signal, It is a resonant inductor The current, It is a magnetizing inductor The current, It is a diode The current at both ends, It is a resonant capacitor. The voltage across the two ends. The resonant current in the circuit is visible. There was a long period of time and excitation current The overlapping region, i.e., when the circuit enters the linear region, means that current flows only through the diode. No flow through the resonant capacitor .

[0041] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A single-stage isolated three-phase AC / DC converter circuit, characterized in that, The circuit is sequentially connected to a three-phase AC input terminal, an input filter module, a high-frequency isolation module, a three-phase full-bridge converter module, a secondary resonant rectifier module, and a DC output module. The three-phase AC input terminal passes the three-phase source through the input filter module to filter out input noise. The current filtered by the input filter module flows into the high-frequency isolation module. The primary side of the transformer in the high-frequency isolation module is connected to the midpoint of the three bridge arms in the three-phase full-bridge converter module, and the secondary side of the transformer is connected to the secondary resonant rectifier module. The secondary resonant rectifier module rectifies the current and then connects it to the DC output module.

2. The single-stage isolated three-phase AC / DC converter circuit according to claim 1, characterized in that, The three-phase AC input terminal is connected to a three-phase AC power supply. , , ; , , Connected to the input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal; The output terminal is connected to the filter inductor in the input filter module. The input terminal.

3. The single-stage isolated three-phase AC / DC converter circuit according to claim 2, characterized in that, In the input filtering module, the filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter inductor The output terminal is connected to the primary magnetizing inductor of the high-frequency isolation module. ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module ; Filter capacitor One end is connected to a filter inductor and the primary side magnetizing inductor of the high-frequency isolation module Filter capacitor , and The other end is grounded.

4. The single-stage isolated three-phase AC / DC converter circuit according to claim 3, characterized in that, In the high-frequency isolation module, the transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and The drain of the transformer One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end; transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Drain of transformer; One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end; transformer excitation inductor One end is connected to the filter inductor The output is connected to the power switch in the three-phase full-bridge converter module, and the other end is connected to the power switch. The source pole and Drain of transformer; One end of the secondary winding is connected to the resonant inductor in the secondary resonant rectifier module. The input is connected to the rectifier capacitor in the secondary resonant rectifier module, and the other end is connected to the rectifier capacitor. one end and One end.

5. A single-stage isolated three-phase AC / DC converter circuit according to claim 4, characterized in that, The magnetizing inductance of the three transformers in the high-frequency isolation module , , Using magnetic integration technology, three excitation inductors are wound together on the same integrated magnetic core, and a three-phase three-limb magnetic core or a three-phase five-limb magnetic core is selected.

6. A single-stage isolated three-phase AC / DC converter circuit according to claim 5, characterized in that, In the three-phase full-bridge converter module, the power switching transistors Drain, Drain and The drains are connected together and then connected to the bus capacitor. one end and the first resonant capacitor One end; power switching transistor The source pole, The source pole and The sources are connected together and connected to the bus capacitor. The other end and the second resonant capacitor One end; first resonant capacitor The other end and the second resonant capacitor The other end is grounded.

7. A single-stage isolated three-phase AC / DC converter circuit according to claim 6, characterized in that, The second resonant capacitor in the three-phase full-bridge converter module Do not connect, only retain the first resonant capacitor. .

8. A single-stage isolated three-phase AC / DC converter circuit according to claim 6, characterized in that, The first resonant capacitor in the three-phase full-bridge converter module First diode connected in parallel at both ends Meanwhile, the second resonant capacitor A second diode is connected in parallel at both ends. .

9. A single-stage isolated three-phase AC / DC converter circuit according to claim 8, characterized in that, The first diode in the three-phase full-bridge converter module Second diode Replace it with two switches.

10. A single-stage isolated three-phase AC / DC converter circuit according to any one of claims 7 to 9, characterized in that, In the secondary resonant rectifier module, the resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; resonant inductor One end is connected to the high-frequency isolation module. The other end of the secondary winding is connected to the DC blocking capacitor. One end; rectifier diode anode and The cathode is connected and connected to the DC blocking capacitor. The other end; rectifier diode cathode, cathode and The cathode is connected to the rectifier capacitor. The other end and the filter capacitor in the DC output module One end is connected; rectifier diode anode, anode and The anode is connected to the rectifier capacitor. The other end and the filter capacitor in the DC output module The other end is connected.

11. A single-stage isolated three-phase AC / DC converter circuit according to claim 10, characterized in that, The resonant inductor , , The transformer primary side of the high-frequency isolation module is placed with the transformer... , , of , , Series connection.

12. A single-stage isolated three-phase AC / DC converter circuit according to claim 11, characterized in that, In the DC output module, the load Parallel connection to the output filter capacitor At both ends, the current rectified by the secondary resonant rectifier module passes through the output filter capacitor. After filtering, the load is supplied. powered by.

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